THE MEASUREMENT OF BLOOD OXYGEN IN MALARIA WITH THE USE OF THE OXIMETER     

Wong YT 《Science (New York, N.Y.)》1945,102(2646):278-279

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Pre-maturity α-amylase and incipient sprouting in UK winter wheat,with special reference to the variety Rialto     

A.?F.?Tjin?Wong?Joe  R.?W.?Summers  G.?D.?Lunn  M.?D.?Atkinson  P.?S.?KettlewellEmail author 《Euphytica》2005,143(3):265-269

In 1998 and 1999 the UK winter wheat variety Rialto produced unexpected low Hagberg falling numbers that could not be directly linked to sprouting. It was proposed that these reductions in quality could be due to pre-maturity α-amylase activity (PMAA). The problem was not identified during the selection and commercial development stages. Our study tested the hypothesis that the variety Rialto is PMAA-susceptible. Analysis was done on 13 year-location combinations of field grown Rialto. Together, visual and chemical assessments of sprouting and iso-electric focusing of α-amylase isozymes identified several samples with significant α-amylase activity in the apparent absence of sprouting. In addition, tests with α-amylase sensitive Phadebas gel revealed distinctive PMAA discoloration patterns in 10–44% of the grain from the 13 samples, leading to the conclusion that Rialto is PMAA-susceptible. Diurnal temperature range accumulated for an 11 day period during a warm spell in early simulated grain development displayed a significant but negative correlation with the number of grains showing clear PMAA discoloration patterns on Phadebas gel. The number of clear PMAA grains correlated positively with rainfall accumulated over 11 days. These results suggest that PMAA can increase under conditions similar to those conducive to pre-harvest sprouting. It is however also possible that in some instances both PMAA and incipient sprouting could have produced similar patterns of α-amylase activity. In addition to tests with Rialto, Phadebas gel tests were therefore also done with the known high Hagberg varieties Option and Malacca, sprouted in a controlled environment. Results from the additional gel tests suggest that visual and chemical assessments of sprouting in the grain combined with Phadebas gel analysis could identify PMAA more reliably in grain sub-samples than Phadebas gel analysis alone.  相似文献   

Availability of Heavy Metals for Brassica Chinensis Grown in an Acidic Loamy Soil Amended with a Domestic and an Industrial Sewage Sludge   总被引：1，自引：0，他引：1  

Wong  J. W. C.  Lai  K. M.  Su  D. S.  Fang  M. 《Water, air, and soil pollution》2001,128(3-4):339-353

The use of sewage sludge on agriculture provides an alternativefor sewage sludge disposal. Therefore, it was the aim of thepresent study to evaluate the feasibility of using a domestic(Tai Po sludge) and an industrial (Yuen Long sludge) sewagesludge produced in Hong Kong for the growth of vegetable crops.The acidic loamy soil with or without lime treatment was amendedseparately with each sludge at application rates of 0, 5, 10, 25and 50% (v/v) for the growth of a common local vegetable crop,Brassica chinensis. The plant available metal contents, asindicated by the DTPA extraction, increased with an increase insludge amendment, but decreased with lime amendment at eachsludge application rate due to the reduced metal availabilityat a higher pH. Sludge amendment enhanced the dry weight yieldof B. chinensis and the increase was more obvious for thesoil with lime treatment. The industrial sludge caused a loweryield than that of the domestic sludge amendment and asignificant reduction in yield at high application rates of YuenLong sludge was also noted. Tissue heavy metal contents, exceptfor Fe, increased as the sludge amendment rate increased whileplant grown in Yuen Long sludge amended soil contained higher Crand Zn contents at each sludge application rate. Liming the soilreduced the heavy metal contents in the plant tissues, exceptfor Fe, which were all below the allowable levels for vegetablecrops. The present experiment demonstrates that liming wasimportant in facilitating the growth of B. chinensis in sludge amended soil. The optimal sludge amendment rate for thesoil with lime amendment was 25% Tai Po sludge and 10% YuenLong sludge, while for the soil without lime amendment was 10% and5%, respectively.  相似文献   

Photodecomposition of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in water     

D G Crosby  A S Wong 《Journal of agricultural and food chemistry》1973,21(6):1052-1054

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Toxic effect of landfill leachate on microalgae     

K. C. Cheung  L. M. Chu  M. H. Wong 《Water, air, and soil pollution》1993,69(3-4):337-349

Leachates from two landfills, namely Junk Bay (JB) and Gin Drinkers' Bay (GDB), were assessed for their acute toxicity using four green algal species, Chlorella pyrenoidosa, C. vulgaris, Scenedesmus sp. and Dunaliella tertiolecta. JB leachate was more toxic to the four algal species tested than leachate from GDB landfill. The growth rates of all four species in 50% JB leachate, and two species (C. vulgaris and D. tertiolecta) in 50% GDB leachate were significantly lower (P<0.05) than those in the control (Bristol Medium only). Values of 96h-EC50 of JB leachate for all four species were lower than those of GDB. The high contents of ammoniacal-nitrogen and organic compounds (such as volatile fatty acids) seemed to be the factors governing the toxicity of leachate on algae. There were differential sensitivities to leachate exhibited by the tested algal species. Susceptibility to leachates in terms of cell number were in the ascending order of C. pyrenoidosa, Scenedesmus sp., C. vulgaris and D. tertiolecta.  相似文献   

Interactions between earthworms, trees, soil nutrition and metal mobility in amended Pb/Zn mine tailings from Guangdong, China     

Y. MaN.M. Dickinson  M.H. Wong 《Soil biology & biochemistry》2003,35(10):1369-1379

This paper reports research that attempts to rehabilitate toxic Pb/Zn mine tailings, in Guangdong, China, to achieve a healthy functional soil that supports sustainable vegetation. We studied the effects of the earthworm Pheretima guillelmi on the growth of a woody legume Leucaena leucocephala on Pb/Zn mine tailings diluted with varying amounts of mineral soil in pot experiments. L. leucocephala grew successfully on tailings with a 25% (w/w) soil amendment, but P. guillelmi only survived and actively burrowed with a 50% soil amendment. The presence of earthworms improved the yield of plants by 10-30%. Whilst earthworms marginally increased available N and P in soil, they increased uptake of phosphorus (by about 10%) to above-ground plant tissues. Six-month-old plants were more sensitive than 10-month plants to metal stress. P. guillelmi increased bioavailable metal concentrations in the amended spoils, accompanied by a direct increase of metal uptake by the plants. Increased metal uptake by plants was largely due to the higher dry matter production stimulated by earthworm activity, but this increased the rate of metal uptake into plants from spoil by at least 16% and as much as 53%. These results demonstrate that we should broaden the ecological context of phytoremediation by considering the plant-soil-animal interactions that influence metal mobility.  相似文献   

Identification of three triterpenoids in almond hulls     

Takeoka G  Dao L  Teranishi R  Wong R  Flessa S  Harden L  Edwards R 《Journal of agricultural and food chemistry》2000,48(8):3437-3439

Three triterpenoids, betulinic acid, oleanolic acid, and ursolic acid, were isolated as their methyl esters (treatment with diazomethane) from diethyl ether extracts of almond hulls (Nonpareil variety) using flash chromatography and preparative high-performance liquid chromatography. The triterpenoids, which comprised approximately 1% of the hulls, were characterized using chromatographic and spectroscopic methods. These studies demonstrate that almond hulls are a rich source of these triterpenoids, which have reported anti-inflammatory, anti-HIV, and anti-cancer activities.  相似文献   

Fatty acid composition and squalene content of the marine microalga Schizochytrium mangrovei     

Jiang Y  Fan KW  Wong RT  Chen F 《Journal of agricultural and food chemistry》2004,52(5):1196-1200

Certain species of thraustochytrids are being explored as potential producer of polyunsaturated fatty acids for nutritional enrichment of food products and use as feed additives in aquaculture. The fatty acid composition and squalene content were determined in the thraustochytrid, Schizochytrium mangrovei that was newly isolated from decaying Kandelia candel leaves in Hong Kong mangrove habitat. The major fatty acid constituents identified in all three S. mangrovei strains were tetradeanoic acid (C14:0), hexadecanoic acid (C16:0), docosapentaenoic acid (C22:5 n-6, DPA) and docosahexaenoic acid (C22:6 n-3, DHA). DHA was the most predominant polyunsaturated fatty acid, and the percentage of DHA (of total fatty acids) in all these strains varied from 32.29 to 39.14%. Only slight changes were observed in fatty acid composition of the S. mangrovei strains harvested at their early (day 3) and late stationary (day 5) phases. In contrast, the cellular squalene content was affected significantly by the culture time; the largest decrease of squalene content from 0.162 mg/g to 0.035 mg/g was found in S. mangrovei FB1 as the culture aged.  相似文献   

A map of the interactome network of the metazoan C. elegans   总被引：1，自引：0，他引：1  

Li S  Armstrong CM  Bertin N  Ge H  Milstein S  Boxem M  Vidalain PO  Han JD  Chesneau A  Hao T  Goldberg DS  Li N  Martinez M  Rual JF  Lamesch P  Xu L  Tewari M  Wong SL  Zhang LV  Berriz GF  Jacotot L  Vaglio P  Reboul J  Hirozane-Kishikawa T  Li Q  Gabel HW  Elewa A  Baumgartner B  Rose DJ  Yu H  Bosak S  Sequerra R  Fraser A  Mango SE  Saxton WM  Strome S  Van Den Heuvel S  Piano F  Vandenhaute J  Sardet C  Gerstein M  Doucette-Stamm L  Gunsalus KC  Harper JW  Cusick ME  Roth FP  Hill DE  Vidal M 《Science (New York, N.Y.)》2004,303(5657):540-543

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Observation of covalent intermediates in an enzyme mechanism at atomic resolution     

Heine A  DeSantis G  Luz JG  Mitchell M  Wong CH  Wilson IA 《Science (New York, N.Y.)》2001,294(5541):369-374

In classical enzymology, intermediates and transition states in a catalytic mechanism are usually inferred from a series of biochemical experiments. Here, we derive an enzyme mechanism from true atomic-resolution x-ray structures of reaction intermediates. Two ultra-high resolution structures of wild-type and mutant d-2-deoxyribose-5-phosphate (DRP) aldolase complexes with DRP at 1.05 and 1.10 angstroms unambiguously identify the postulated covalent carbinolamine and Schiff base intermediates in the aldolase mechanism. In combination with site-directed mutagenesis and (1)H nuclear magnetic resonance, we can now propose how the heretofore elusive C-2 proton abstraction step and the overall stereochemical course are accomplished. A proton relay system appears to activate a conserved active-site water that functions as the critical mediator for proton transfer.  相似文献